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PCB set for DIY SSB HAM Shortwave Receiver NE612, 1:9 Balun, Band Pass Filter

Availability: Out of stock

$19.50

Quick Overview

3pcs PCB set for DIY Shortwave SSB Receiver Project. The circuit is based on two NE612 and one LM386. The circuit is pretty standard and the board is universal type for any SSB band you wish. The default manual instruction available for 20M band (14.000MHz - 14.350MHz) receiver. The main board support connection of DDS AD9850 module if you want to make digital tuning.

PCB set for DIY HF HAM SSB Receiver NE612

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  • PCB set for DIY HF HAM SSB Receiver NE612
  • SSB Receiver Demo circuit
  • SSB Receiver Demo Manual

Details

 



This is PCB set kit that includes 3pcs of high quality printed boards for Superhet Receiver:


1pcs Main Board PCB

1pcs Mini Balun 1:9 PCB for Beverage Antenna

1pcs Band Pass Filter PCB

1pcs Full detailed electrical circuit for 20M Receiver and link to download instruction PDF


Take note, the purchase includes only PCB's, without components. To get full parts list you need for that project please follow the link:


DOWNLOAD FULL PARTS LIST FOR SSB RECEIVER PROJECT

DOWNLOAD CALIBRATION INSTRUCTION PDF with CIRCUIT

 

The receiver is a simple superheterodyne type with quartz crystal filter. The circuit is based on two NE612 mixer IC’s and one audio amplifier LM386. The original electrical circuit as it described in the manual is intended for 14.000MHz – 14.350MHz upper single side band receiving of amateur radio transmissions. However, the PCB allows modifying it for all others amateur SSB radio bands, or making it 2 bands receiver if required. PCB is also support AD9850 module connection if you prefer digital tuning.


If you are beginner it’s strongly recommended to ask someone's help from your local radio club to help you with components selecting and receiver assembling. The syperhet calibration requires you to have an oscilloscope, DDS HF signal generator, LC Meter, multimeter and soldering tools. Moreover, it requires some basic knowledge of “how it works” for correct pre-set of the board. That’s why I recommend to ask help of someone experienced if you get trouble with receiver calibration. My remote support will be very limited, so I advice this purchase for experienced builders or for Radio Club project teams.

Follow the link for EXAMPLE SSB RECEIVER PROJECT description.

PCB kit for SSB Receiever

Superheterodyne Receiver Calibration:

Trim LM317 output for 7V DC. Before any IC's is inserted into the sockets connect regulated 9V power supply and trim R29 for the 7V voltage output on pin#2 of LM317. After that check all VDD points read correct voltage. Check with the scope that LM317 output does not oscillate for some reason.

 

Install LM386 and connect phones. Insert weak audio signal of several mV to check that audio amplification stage is working. Be careful not to overload LM386 input with powerful signals, you can inject small signal by using potentiometer divider.

 

Check Crystal Filter Bandwidth. Connect oscilloscope to pin#1 of the IC2 DIP socket (NE612 still not installed). Connect HF DDS sinusoidal function generator to pin#4 of IC1 DIP socket. Insert IF frequency signal of 4.194MHz from DDS. The amplitude of the signal need to be 200mV-400mV VPP. Sweep the generator +-10KHz. Check the filter bandwidth does not exceed 4KHz. Use R5 to trim the bandwidth and L5, L6 for filter matching. I use slow oscilloscope horizontal scanning for that purpose and sweep DDS manually to observe the amplitude of the output filter signal. Write the filter frequencies pandpass, for example it will be something like 4.193-4.197MHz. Later you’ll readjust R5 a little with real signal receiving.

 

BFO frequency adjustment. Insert IC2 into the socket. The L8 coil intended to shift down BFO Q6 crystal frequency. Connect frequency counter or digital oscilloscope to BFO control point.   

 

faudio = |fIF - fBFO|   

 

Let's say that the resulting crystal filter had -6dB points at 4.193 and 4.196MHz (bandwidth of 3kHz). The location of the BFO relative to the passband sets the audio frequency response of the radio, so if you want your bandwidth from 400 to 3400 Hz you would set the BFO 400Hz from the edge of the passband. Varying the BFO allows you to trade off between high and low frequency response. Generally you don't want to get much below 300 Hz because there is less rejection of the carrier and opposite sideband. There is some room for adjustment here because the crystal filter won't have perfectly steep sides.

 

But which side of the passband? That depends on which sideband you want. If the BFO is above the passband (4.200 MHz) you will get lower sideband (LSB), and if the BFO is below the passband (4.190 MHz) you get upper sideband (USB). Unless, of course, the receiver uses high side injection (frequency difference) in one of the mixer stages, which causes a sideband reversal.

 

Usually for frequencies below 10MHz LSB is used, and for frequency over 10MHz USB is in use. For CW or digital stations you need narrow 200Hz-400Hz bandwidth. For voice receiving the bandwidth need to be between 2200Hz-3500Hz.

 

VFO frequency adjustment. Insert IC1 into the socket. The frequency of the VFO depends on L4, C10, C16, C15, CD1 values. Connect frequency counter or digital oscilloscope to VFO control point.

VFO Frequency range for 20M and 4.194MHz IF: 9800KHz - 10160KHz

Example for station with frequency of 14.100MHz:

14.100MHz = 4.194MHz(IF) + 9.906MHz(VFO)

For analog manual trimming I recommend to wire two multiturn resistors of 10K+1K for R4. Be sure that you cover all range of 9800KHz-10160KHz for VFO. If your range is bigger than required then measure DC varicap voltage range you need for 20M band and use additional resistor before or after R4 to limit it.

If you use frequency synthesizer for trimming, the NE612 works fine with AD9850 or any other HF generator. The amplitude of the signal can be 100mV-200mV VPP connected to pin#6 of IC1 via 10nF capacitor.

 



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